Page 28 - Blog Posts v1

Using an IPL with the wrong filters will also induce very high temperature in darker skins.
What these calculations show is that surface skin cooling is critical as the skin colours darkens – whether it’s a ‘natural’ skin colour or a tan. It is an unfortunate fact of physics that a small increase in fluence results in a large (exponential) increase in tissue damage – which is great when trying to destroy germ cells in follicles, but not so good when we consider the epidermis.
Conclusion
The bottom line is that we are trying to remove hair permanently from people’s skin – across a wide range of skin colours. The science shows that to do this we MUST apply the correct fluence, which depends on the hair colour and depth. It does NOT depend on the skin colour - that is completely unrelated.
But the skin colour is directly related to epidermal damage and pain. To alleviate the pain sensations we must apply plenty of cooling – before, during and after the treatment. This will suck much of the excess heat energy located in the basal layer (which is not that far from the surface!), resulting in much lower temperatures there.
I know this will go ‘against the grain’ of current thinking, but the physics is very simple. Reducing the fluence to ‘compensate’ for skin colour is quite wrong!!
Ciao for now, Mike.
Mike’s Blog Posts 28